In many countries, waste material is collected and taken to processing centres or recycling centres. Some categories of waste are separated out and sent to recycling processes, either at the centre or elsewhere. For example, waste glass is commonly recycled. Waste that is not recycled may be sent to landfill or may be burnt, typically to provide either heat or electrical energy.
Large amounts of plastic are used in modern goods and packaging and there is therefore a large quantity of plastic waste, typically termed Mixed Plastic Waste, passing through recycling centres. Typically, PET and HDPE are separated out for recycling and the remainder is sent to landfill. However, landfill may not be a popular option and there therefore exists a need to find other ways of dealing with Mixed Plastic Waste, either on its own or combined with organic material as Municipal Solid Waste.
Some solutions have been proposed for Mixed Plastic Waste. For example, Mixed Plastic Waste may be used as a fuel in a power station. However, the cost of electricity generated in such a way may be ten times the cost of electricity generated from a conventional fossil fuel, such as natural gas. It may also be difficult to use all the heat produced in such processes and much of it is therefore dissipated in cooling towers. The combination of low efficiency and high capital cost can make such solutions unattractive.
Pyrolysis of Mixed Plastic waste has been suggested as a solution. Examples include the use of pyrolysis to create fuel for vehicles, combining pyrolysis with plasma treatment to produce hydrogen and pyrolysis for disposal of plastic waste at sea. However, such processes may suffer from drawbacks, including the difficulty of producing a uniform, high-quality product from a highly variable feed such as waste and the difficulty of effectively using all the pyrolysis products.
The present invention seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved process and apparatus for the treatment of waste comprising Mixed Plastic Waste.